The present invention relates to improvements in apparatus for heating, drying and/or cooling of relatively thin objects, such as freshly printed plates, webs or sheets of paper, synthetic plastic material, textile material and/or metal as well as numerous other objects including discrete components of electronic devices and the like.
German Pat. No. 26 07 504 discloses a drying apparatus with a series of stationary suction boxes or chambers which are disposed one after the other. A web or strip of material to be dried is transported at a level above the suction chambers. If the material to be treated includes a plurality of discrete objects, they are transported along successive suction chambers by a conveyor system. A drawback of the patented apparatus is that its space requirements are inordinately large as well as that it consumes substantial quantities of energy. The conveyor system includes a screen which is in rubbing contact with the stationary suction chambers so that such parts undergo pronounced wear with attendant high maintenance cost. Moreover, the prime mover which transports the screen must exert a pronounced pull in order to overcome friction between the conveyor system and the suction chambers.
German Offenlegungsschrift No. 31 03 421 discloses a rotary drying apparatus which includes a driven heated drum whose external surface is contacted by rather long and flat web-like objects issuing from a screen printing machine. The drum is not ideally suited for the drying and/or other treatment of discrete objects, such as small flexible sheets or plates. Furthermore, the drum cannot be used for uniform drying of rigid flat objects due to the pronounced curvature of its external surface. Moreover, the drying apparatus of the German publication is not equipped with any means for supplying discrete objects to and/or for accepting treated objects from the drum.